Cleaned up the README. Copied some constants and struct definitions to buse.h so

that the code doesn't rely on a hard-coded location of nbd.h.

Makefile

@@ -4,7 +4,7 @@ OBJS		:= $(TARGET:=.o) $(LIBOBJS)
 STATIC_LIB	:= libbuse.a
 
 CC			:= /usr/bin/gcc
-CFLAGS		:= -g -pedantic -Wall -Wextra -std=c99 -I$(HOME)/src/nbd
+CFLAGS		:= -g -pedantic -Wall -Wextra -std=c99
 LDFLAGS		:= -L. -lbuse
 
 .PHONY: all clean

README

@@ -1,14 +1,12 @@
-BUSE - A block device in user space
+BUSE - A block device in userspace
 
 Adam Cozzette
 Fall 2011
 
-This piece of code was inspired by FUSE, which allows the development of Linux
-file systems that run in user space. The goal of BUSE is to allow virtual block
-devices to run in user space as well.
-
-Currently BUSE is a work in progress and the existing code is hacked together.
-Soon I hope to finish implementing everything robustly.
+This piece of software was inspired by FUSE, which allows the development of
+Linux file systems that run in userspace. The goal of BUSE is to allow virtual
+block devices to run in userspace as well. Currently BUSE is experimental and
+should not be used for production code.
 
 Implementing a block device with BUSE is fairly straightforward. Simply fill
 struct buse_operations (declared in buse.h) with function pointers that define
@@ -19,5 +17,5 @@ struct. busexmp.c is a simple example example that shows how this is done.
 The implementation of BUSE itself relies on NBD, the Linux network block device,
 which allows a remote machine to serve requests for reads and writes to a
 virtual block device on the local machine. BUSE sets up an NBD server and client
-on the same machine, with the server running executing the code defined by the
-BUSE user.
+on the same machine, with the server executing the code defined by the BUSE
+user.

buse.c

@@ -2,7 +2,6 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <linux/types.h>
-#include <nbd.h>
 #include <netinet/in.h>
 #include <stdio.h>
 #include <stdlib.h>

buse.h

@@ -1,8 +1,57 @@
 #ifndef BUSE_H_INCLUDED
 #define BUSE_H_INCLUDED
 
+/* Most of this file was copied from nbd.h in the nbd distribution. */
+
+#include <linux/types.h>
 #include <sys/types.h>
 
+#define NBD_SET_SOCK	_IO( 0xab, 0 )
+#define NBD_SET_BLKSIZE	_IO( 0xab, 1 )
+#define NBD_SET_SIZE	_IO( 0xab, 2 )
+#define NBD_DO_IT	_IO( 0xab, 3 )
+#define NBD_CLEAR_SOCK	_IO( 0xab, 4 )
+#define NBD_CLEAR_QUE	_IO( 0xab, 5 )
+#define NBD_PRINT_DEBUG	_IO( 0xab, 6 )
+#define NBD_SET_SIZE_BLOCKS	_IO( 0xab, 7 )
+#define NBD_DISCONNECT  _IO( 0xab, 8 )
+#define NBD_SET_TIMEOUT _IO( 0xab, 9 )
+#define NBD_SET_FLAGS _IO( 0xab, 10 )
+
+enum {
+	NBD_CMD_READ = 0,
+	NBD_CMD_WRITE = 1,
+	NBD_CMD_DISC = 2,
+	NBD_CMD_FLUSH = 3,
+	NBD_CMD_TRIM = 4
+};
+
+/* Magic numbers */
+#define NBD_REQUEST_MAGIC 0x25609513
+#define NBD_REPLY_MAGIC 0x67446698
+
+/*
+ * This is the packet used for communication between client and
+ * server. All data are in network byte order.
+ */
+struct nbd_request {
+	__be32 magic;
+	__be32 type;	/* == READ || == WRITE 	*/
+	char handle[8];
+	__be64 from;
+	__be32 len;
+} __attribute__ ((packed));
+
+/*
+ * This is the reply packet that nbd-server sends back to the client after
+ * it has completed an I/O request (or an error occurs).
+ */
+struct nbd_reply {
+	__be32 magic;
+	__be32 error;		/* 0 = ok, else error	*/
+	char handle[8];		/* handle you got from request	*/
+};
+
 struct buse_operations {
     int (*read)(void *buf, u_int32_t len, u_int64_t offset);
     int (*write)(const void *buf, u_int32_t len, u_int64_t offset);